Improvement in bed-bottoms



UNITED STATES PATENT OFFICE.

LEWIS BIRK, OF GANAJOHARIE, NEW YORK, ASSIGNOR OF ONE-HALF HIS RIGHT TOGEORGE D. GEBAUER, OF SAME PLAGE.

IMPROVEMENT IN BED-BOTTOMS.

Specification forming part of Letters Patent No. 179,257, dated June 27,1876 application tiled March 8, 1876.

ydrawing, and to the letters of reference marked thereon, which form apart ot' this specification.

My improved bed-bottom is designed to ai ford increased resistance to anincrease ofthe weight, and the arrangement of the springs is designedfor that purpose, the prime supports for the bed-bottom being cornervolute springs, and with these intermediate volute springs of a heightat least one-third less than the corner springs are used, and only comein spring resistance when additional weightis carried by the bed. Thesesprings rest upon a base-frame, and are secured in place by loose rodspassing through them, and by which the bed-bottom and the base-frame areconnected. The top coils of the volute springs embrace these rodssnugly, and are thereby held from twisting out ot' line at the top. Asthese springs are of greater diameter at their base, to allow theircoils to fold one within the other when compressed, they would be liableto shift from a vertical central line and cause the spring to standcrooked and on one edge at its base, and hence become jammed whencompressed. To avoid this, I combine with the volute spring and itscentral conflnlng-rod a base-retainer, through which the confining-rodpasses, and which, being concentric with the lower foldof the spring,forms an interior side bearing and support for the largest end of thevolute and braces, and keeps it in position concentric with the upperend, so that the compression of all the springs will be free and withoutliability to be injured or broken, as would be the case without theconcentric base-retainer,to preserve the verticalbearing positions ofthese springs. Especially are the central bracing base-retainers ofadvantage with the intermediate springs, as these are supported inposition by free headed rods, and would thereby be liable to get out ofcentral position, and be crushed by the bed-bottom striking upon thefree head ot' the holdingrod. These intermediate springs act inconjunction with the cornerlsprings, andare designed only to support theincreased Weight of two persons, whereby a more uniform springbed-bottom is obtained, than when all the springs are arranged to act atonce.

j In the accompanying drawings, Figure l represents a side view of myimproved bedbottom, with the springs at rest; Fig. 2, a similar view,with all the springs in play to resist a greater weight.; and Fig. 3, asection through the line of volute springs, showing the base concentricretainers in connection with the central holding-rods, by which the baseof the springs are kept in line and braced at the enlarged base coils.

The sacking bottom A, or bottom proper, is supported at its four cornersby volute springs B, contined in position by rods a, which pass throughsaid springs and through holes in the bed-bottom frame- A, and the basespringsupporting frame C, coincident therewith, or with thebedstead-trame itself. The bases of the springs B rest upon this frameO, while they yield to the pressure from the frame A above.Intermediately between these cornersprings B, and upon the side bars ofthe frame C, are volute springs D, of less height by about one-thirdthan the corner-springs, and they are confined vertically by loose rodsb, which, however, only pass through the lower frame, and their lengthdoes not exceed the height ot' .the springs which surround them, so thatthe pressure of the bed-frame is received directly upon the heads ot'these bolts.

Ihe upper coils of the volute springs t quite close around the bolts ab, and are thus held from twisting out of line; but as the basecoils areof increased diameter, they would be liable to shift out of line andbear only at one side of the rod, and the spring thereby becomes jammedwhen compressed, and stand oblique, so that it would be comparativelyuseless. rIhis I avoid by combining withthe base of the spring and thecentral holdingrods a b, an interior concentric retaining-core,

' the springs, and'theymay be made slightly tapering. They are fastenedto the base-frame C, and thereby serve the additional advantage ofpreventing the frame splitting where the rods pass through it.

I may use one or more of the short springs D at proper intervals, and atthe ends as Well as at the sides. I nd, however, in practice, that thetwo free springs D, one upon each A side of the bed-bottom, suicientlyanswer the purpose, which is to accommodate difterent weights withoutdestroying the springy resistance, so much desired. The rods forconfining the-springs are provided with screwy nuts, for holding them inplace.

I claim- 1. In a spring bed-bottom, the combination of the corner volutespring B, supported by rods a, and the intermediate short springs D,held by loose rods b, as described, for the purpose of compensating fordifferent weights and still preserving thev desired springy resistance,as set forth.

2. The combination, with the volute springs, the centralconnecting-rods, and the basefra'me C, of the interior supporting andbrac ing cores c, for the base-coils of said springs, vas described.

In testimony that I claim the foregoing I have affixed my signature inpresence of two witnesses.

LEWIS BIRK. vWitnesses:

ABM. NELLIS,

GEORGE SWAR'rs.

